athere is one right over there 在那有一权利[translate] acycle time inlet valve exceeded 正在翻译,请等待...[translate] aIn chemical reactions, atoms of one element are changed into atoms of another element. 在化学反应,一个元素原子被改变到另一个元素原子。[translate]...
1. A chemical change takes place in any substance when it burns. 物质燃烧时产生化学变化。 2. He devoted his life to chemical research. 他一生从事化学研究。 名词 1. He is experimenting with a new chemical. 他正在实验一种新的化学制品。
Chemical reactions take place when the atoms of two or more substances exchange or share electrons. The reaction produces atoms and molecules with the electrons arranged differently. The changed configuration of the atoms involves a change in energy, meaning the chemical reaction either gives off or ...
Physical changes are changes in a substance that do not change its identity. Physical changes can change the appearance of a substance, but they never change its composition. For example, chemical bonds do not break, and atoms are not rearranged. One notable type of physical change is the pha...
Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of th
regarded as formed from the acidic and basic oxides, as sulfates, carbonates, silicates, aluminates, and phosphates. Plentiful as they are, these solid compounds are not useful as sources of oxygen, because separation of the element from its tight combinations with themetalatoms is too expensive...
athe chemical potentials of the metal atoms can change as long as the relative fractions Ym=Xm= mXm of the metal atom species m = Fe, Cr, Ni remain constant – except in a nar-rowregiononthecsideofthecarbide–cinterface: toestab-sh a local equilibrium, the concentration profiles of the...
Chemical formulas describe the type and number of atoms within a compound. The molecular formula lists the symbol of each element within the compound followed by a number (usually in subscript). The letter and number indicate how many of each type of ele
(Chemistry) a process that involves changes in the structure and energy content of atoms, molecules, or ions but not their nuclei. Comparenuclear reaction Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 200...
Chemical compound, any substance composed of identical molecules consisting of atoms of two or more chemical elements. All the matter in the universe is composed of the atoms of more than 100 different chemical elements, which are found both in pure form